TWI743847B - Electrode material and preparation method thereof - Google Patents

Abstract

An electrode material and a preparation method thereof are provided. The electrode material includes a particle and a charged irregular geometric porous structure disposed on the particle. A material of the particle includes silicon, silicon oxide, metal, metal oxide, carbon, graphite or a composite material thereof.

Description

Electrode material and its preparation method

The invention relates to an electrode material and a preparation method thereof, and particularly relates to a lithium ion battery negative electrode material and a preparation method thereof.

In the existing lithium battery industry, the negative electrode is mainly graphite materials such as natural graphite or artificial graphite. Because graphite has the essential characteristics of low electrochemical potential, and its layered structure also happens to be suitable for the migration and storage of lithium ions. In addition, the rate of volume change caused by graphite during charging and discharging is small, and therefore, it has become the mainstream material for the negative electrode of commercial lithium batteries. However, in recent years, due to the lightweight and long-term output of 3C vehicles and electric vehicles, the requirements for battery energy density have also increased rapidly ^{. Graphite with a theoretical specific capacitance of only 372mAhg -1} has gradually been unable to meet the needs of future energy storage batteries. In contrast, lithium-silicon compounds with 9 to 11 times the graphite specific capacitance have become the mainstream technology development of high energy density anode materials.

However, due to the high storage capacity of silicon for lithium ions, the silicon lattice is forced to produce about 400% volume expansion when alloying with lithium ions. This high volume expansion rate will cause the silicon to separate from each other, causing the electrode to peel off from the current collector after powdering. In addition, the contact area between silicon and the electrode is reduced and the distance is elongated, and the electric field cannot effectively act on the electrode. Therefore, lithium ions and electrons cannot be effectively used, resulting in a rapid decline in battery cycle times and greatly reducing battery life. On the other hand, intrinsic silicon itself has poor conductivity, resulting in high internal resistance and slow heat dissipation, which also greatly affects the performance of the battery. Based on the above, how to prevent the silicon electrode from falling off and increase the ability of the silicon electrode to conduct electrons to increase the cycle life of the silicon anode is the most important issue that must be overcome in the current commercialization of the silicon anode.

The invention provides an electrode material and a preparation method thereof. After particles, a carbon source and a solvent are mixed, a charged irregular geometric pore structure is generated on the particle surface through high-temperature sintering, thereby enhancing the adsorption effect with an adhesive.

The electrode material of the present invention includes particles and charged irregular geometric pore structures arranged on the surface of the particles. The material of the particles includes silicon, silicon oxide, metal, metal oxide, carbon, graphite or their composite materials.

In an embodiment of the present invention, the particle size of the particles is 1 nm to 100 μm.

In an embodiment of the present invention, the metal or metal oxide includes alkali metal, alkaline earth metal or transition metal.

In an embodiment of the present invention, the charged irregular geometric pore structure increases the original surface area of the particles by 2 to 50 times.

The preparation method of the electrode material of the present invention includes the following steps. The particles are mixed with a carbon source and a solvent, and after heat treatment and sintering, a charged irregular geometric pore structure is formed on the surface of the particles. The material of the particles includes silicon, silicon oxide, metal, metal oxide, carbon, graphite or their composite materials.

In an embodiment of the present invention, the heat treatment sintering is performed at a temperature of 200° C. to 1200° C. for 0.1 hour to 100 hours.

In an embodiment of the present invention, the carbon source includes a metal ion-containing hydrocarbon, a metal ion-containing carbohydrate, or a combination thereof.

In an embodiment of the present invention, the carbon source includes alkalized sucrose, cellulose, alkalized phenolic resin, pitch, gum oil coal, or a combination thereof.

In an embodiment of the present invention, the solvent includes water, methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, tetrahydrofuran, benzene, toluene, acetate or a combination thereof.

In an embodiment of the present invention, the charged irregular geometric pore structure increases the original surface area of the particles by 2 to 50 times.

Based on the above, the present invention provides an electrode material and a preparation method thereof. After particles, a carbon source, and a solvent are mixed, a charged irregular geometric pore structure is generated on the surface of the particle through high temperature sintering. The charged irregular geometric pore structure can make the original surface area of the particle Increase, so as to effectively enhance the adsorption effect with the adhesive, thereby improving battery performance.

In this article, the range represented by "a value to another value" is a general way to avoid listing all the values in the range one by one in the specification. Therefore, the record of a specific numerical range covers any numerical value in the numerical range and the smaller numerical range defined by any numerical value in the numerical range, as if the arbitrary numerical value and the smaller numerical value are clearly written in the specification The scope is the same.

The following examples are listed in conjunction with the accompanying drawings for detailed description, but the provided examples are not intended to limit the scope of the present invention. In addition, the drawings are for illustrative purposes only, and are not drawn in accordance with the original dimensions.

Fig. 1 is a schematic diagram of an electrode material according to an embodiment of the present invention. FIG. 2 is a schematic diagram of adsorption of an electrode material and an adhesive according to an embodiment of the present invention.

1, the electrode material of the present invention includes particles 10 and charged irregular geometric hole structure holes 20 arranged on the surface of the particles 10. The charged irregular geometric hole structure 20 is, for example, positively charged, but the present invention does not use this Is limited. In more detail, the main body of the charged irregular geometric hole structure 20 is, for example, composed of carbon and some metal ions, and the charge mainly comes from the metal ions in the carbon source. The material of the particles 10 may include silicon (including pure silicon or modified silicon, which can be surface-modified with silane or a dispersant), silicon oxide, metal, metal oxide, carbon, graphite or their composite materials, metal or metal Oxides can include alkali metals (Li/Na/K), alkaline earth metals (Mg/Ca/Sr/Ba) or transition metals (Ti/Zr/Ta/Cr/W/Mn/Co/Fe/Ni/Cu/Al /Sn/Ge/Ag). In more detail, the dispersant can mainly include silane-based substances. One end of the silane substance is preferably silicophilic, which makes it easier to bond with the silicon surface, and the other end is hydrophilic or hydrophobic (depending on the solution’s affinity for hydrophobicity). Depending on the nature), it can be dispersed in the solution. In this embodiment, the material of the particles 10 is, for example, silicon, and there may be a silicon oxide layer 12 (SiO _x , where X=0.1 to 2) between the particles 10 and the charged irregular geometric hole structure 20, for example, silicon oxide The thickness of the layer 12 is, for example, 0.1 nm to 100 nm, but the present invention is not limited to this. The particle size of the particle 10 is, for example, 1 nm to 100 μm, and the charged irregular geometric pore structure 20 can increase the original surface area of the particle 10 by about 2 to 50 times.

The present invention also provides a preparation method of an electrode material for manufacturing the electrode material of FIG. 1. The preparation method includes: mixing particles with a carbon source and a solvent, wherein the mixing ratio of the particles, the carbon source and the solvent is, for example, 1:0.01 to 10 : 0.1 to 9, after heat treatment and sintering, a charged irregular geometric pore structure is formed on the surface of the particles. In more detail, the heat treatment sintering is performed at a temperature of 200° C. to 1200° C. for 0.1 hour to 100 hours, for example. The carbon source may include carbon containing metal ions (Li/Na/K/Mg/Ca/Sr/Ba/Ti/V/Cr/Mn/Fe/Co/Ni/Cu/Zn/Al/Si/Ge/Ag) Hydrogen compounds, metal ion-containing carbon hydroxides, or combinations thereof. The carbon source may also include alkalized sucrose, cellulose, alkalized phenol resin, pitch, gum oil coal, or a combination thereof. The solvent may include water, methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, tetrahydrofuran, benzene, toluene, acetate, or a combination thereof.

Please refer to FIG. 2, through the charged irregular geometric hole structure 20, the adhesive 30 can be penetrated into the structure of the particle 10, and the non-uniform charge characteristics of the adhesive 30 and the anchor point effect of the charged irregular geometric hole structure 20 can greatly improve the adhesion. The adhesion between the agent 30 and the particles 10 can also use the mechanical strength and toughness of the adhesive 30 to protect the silicon-carbon material from swelling problems, thereby improving the battery life of the silicon-carbon material. In this embodiment, the adhesive 30 is, for example, a negative electrode adhesive, which may include Styrene-Butadiene Rubber (SBR), Poly(acrylic acid) (PAA), Polyimide (PI) , Phenolic resins (PR) or Polyacrylonitrile (PN).

FIG. 3 is a scanning electron microscope (Scanning Electron Microscope, SEM) image of an unprocessed original morphology of particles according to an embodiment of the present invention. 4 is a scanning electron microscope (Scanning Electron Microscope, SEM) image of a particle formed with a charged irregular geometric hole structure according to an embodiment of the present invention.

Referring to FIG. 3, before the preparation method of the electrode material of the present invention, the surface of the untreated particles is smooth. Please refer to FIG. 4, after the preparation method of the electrode material of the present invention is carried out, the surface of the particles is configured with holes with a charged irregular geometric hole structure. In the embodiment shown in FIG. 4, for example, a certain proportion of modified silicon powder, graphite, and alkalized sucrose are mixed to form a uniform solution, dried and molded, and then heat-treated at a high temperature of 800° C. and sintered for 2 hours.

Fig. 5 is a graph showing the performance of an electrode material according to an embodiment of the present invention. After the electrode material of the present invention is made into a button cell using a conventional method ("modified powder" in Figure 5), compare it with a powder not modified by the preparation method of the present invention ("primary powder" in Figure 5) "Body", that is, the particle is not equipped with a charged irregular geometric hole structure). As shown in FIG. 5, compared with the "primary powder" in FIG. 5, the life performance of the "modified powder" using the electrode material of the present invention in FIG. 5 can be greatly improved.

In summary, the present invention provides an electrode material and a preparation method thereof. After particles, a carbon source and a solvent are mixed, a charged irregular geometric pore structure is generated on the surface of the particle through high temperature sintering. The original surface area is increased and the adhesive penetrates into the particle structure, and the non-uniform charge of the adhesive and the anchor effect of the charged irregular geometric pore structure greatly improve the adhesion between the adhesive and the particle. The mechanical strength and the adhesive can also be used. Toughness can protect the silicon-carbon material from swelling problems, thereby improving the battery life of the silicon-carbon material.

10: particles 12: Silicon oxide layer 20: Charged irregular geometric hole structure 30: Adhesive

Fig. 1 is a schematic diagram of an electrode material according to an embodiment of the present invention. FIG. 2 is a schematic diagram of adsorption of an electrode material and an adhesive according to an embodiment of the present invention. FIG. 3 is a scanning electron microscope (Scanning Electron Microscope, SEM) image of an unprocessed original morphology of particles according to an embodiment of the present invention. 4 is a scanning electron microscope (Scanning Electron Microscope, SEM) image of a particle formed with a charged irregular geometric hole structure according to an embodiment of the present invention. Fig. 5 is a graph showing the performance of an electrode material according to an embodiment of the present invention.

10: particles

12: Silicon oxide layer

20: Charged irregular geometric hole structure

30: Adhesive

Claims (9)

An electrode material comprising: particles, the material of the particles includes silicon, silicon oxide, metal, metal oxide, carbon, graphite or their composite materials; and a charged irregular geometric pore structure, arranged on the surface of the particle , The charged irregular geometric pore structure increases the original surface area of the particles by 2 times to 50 times. The electrode material according to the first item of the scope of patent application, wherein the particle size of the particles is 1 nm to 100 μm. The electrode material according to the first item of the scope of patent application, wherein the metal or the metal oxide includes an alkali metal, an alkaline earth metal or a transition metal. A preparation method of electrode material includes: mixing particles with a carbon source and a solvent, and sintering through heat treatment to form a charged irregular geometric pore structure on the surface of the particles, wherein the material of the particles includes silicon and silicon oxide , Metals, metal oxides, carbon, graphite or their composite materials. The method for preparing the electrode material as described in item 4 of the scope of patent application, wherein the heat treatment sintering is performed at a temperature of 200°C to 1200°C for 0.1 hour to 100 hours. The method for preparing an electrode material as described in item 4 of the scope of patent application, wherein the carbon source includes a metal ion-containing hydrocarbon, a metal ion-containing carbohydrate, or a combination thereof. The method for preparing an electrode material as described in item 4 of the scope of patent application, wherein the carbon source includes alkalized sucrose, cellulose, alkalized phenolic resin, pitch, gum oil coal, or a combination thereof. According to the preparation method of the electrode material described in item 4 of the scope of patent application, the solvent includes water, methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, tetrahydrofuran, benzene, toluene, acetate, or a combination thereof. According to the method for preparing the electrode material described in item 4 of the scope of patent application, the charged irregular geometric pore structure increases the original surface area of the particles by 2 to 50 times.

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